Poison ivy: It's getting stronger and tougher

Mark Laliberte is used to getting poison ivy, but the reaction he suffered in July was the worst ever.

The 37-year-old Candia man was clearing brush on his property when he slipped into some bushes.

"I didn't see it, but once I fell into it, I knew it was poison ivy. I ran inside and showered, but it was too late. It was all over my face and neck, particularly on my left side," he said.

Beth Almon's doctor told her she has the worst case of poison ivy she's ever seen. After battling the itch for three weeks, Almon is now on her second batch of Prednisone, a drug used to treat severe allergic reactions.

"This year, for some odd reason I can't get rid of it out of my system," said Almon, 32, of Raymond.

The reason for the severe cases may have something to do with changes in the poison ivy plant caused by higher levels of carbon dioxide in the atmosphere, experts say.

Poison ivy is thriving and becoming much more potent, according to Lewis H. Ziska, a research weed ecologist with the U.S. Department of Agriculture.

Ziska has studied the effects of carbon dioxide on plants and has found that it's changing the chemistry of the urushiol oil in poison ivy, making it more toxic and more likely to cause a skin reaction.

His research looked at how plants react to more sunlight appearing in forests that have become fragmented, especially in urban areas. Ziska found that poison ivy flourishes, spreading faster and becoming more potent.

"Poison ivy tends to do better than most of the plant species we looked at. It's able to take in the additional carbon dioxide and convert it into additional growth," he said.

While she hasn't seen more poison ivy sufferers than usual, Dr. Ellen Bernard of Epping Regional Health Center said there are treatments available to ease the itching and clear things up. Topical steroids can be used, but more severe cases may require an oral steroid.

Susan Chadwick, director of marketing at Derry Medical Center, said she takes steps to avoid poison ivy, but still ended up with a case in July.

"I'm very sensitive to it, so I try like the devil to avoid it," said Chadwick, whose colleague also suffered a severe reaction this summer and ended up on Prednisone.